Method for breaking-up an annular core of ferromagnetic material



Jan. 10, 1956 N. F. MEIER 2,730,471 METHOD FOR BREAKING-UP AN ANNULAR CORE OF FERROMAGNETIC MATERIAL Filed Sept. 8, 1952 INVENTOR NICOLAAS FREDERH MEIER AGENT Unite States Paten METHOD FOR BREAKING-UP AN ANN ULAR CORE OF FERROMAGNETIC MATERIAL Nicolaas Frederik Meier, Eindhoven,

signor to Hartford National Bank and Hartford, Conn, as trustee Netherlands, as-

Trust Company,

Known methods for producing closed ferromagnetic cores include placing a winding on disassembled core segments and then assembling the segments into a closed The pieces of the core should preferably fit together with a minimum airgap. For this purpose it has been proposed to break a core, produced by moulding powdered iron, by applying a suitable mechanical force thereto.

The invention relates to a method for breaking a circular core made of a ferromagnetic polyoxide of spinelstructure of iron and other metals. This material is usu lly obtained by sintering and is comparatively hard and brittle.

which yields a plurality of small flames (7) situated along a vertical line. These flames are directed to the line on the circumference of the wanted, and which may have been marked beforehand by a chalkline.

outside of the ring is heated to a much higher degree than the inside.

The break surface is comparatively smooth and only in exceptional cases do small fragments of the material fly oflf, so that even in rapid production, the reject percentage is limited to a very low value. With the ring occupying a position in which it has turned on its axis through approximately the process is repeated, after Which the ring can be dismantled in two pieces, which after the windings have been placed in position, the ring can be exactly reassembled.

The method described above is particularly suited for mass production because the cooled body.

from the first fracture. scored prior to breaking What I claim is:

1. A method of breaking an annular core made of ferromagnetic polyoxide of spinel structure of iron com prising placing a heat source adjacent said core and locally heating said core to thereby split the same along at least one predetermined line.

2. A method of breaking an annular core made of ferromagnetic polyoxide of spinel structure comprising placing a heat source adjacent said core and locally heating said core by means of a plurality of small flames arranged in a line.

3. A method of breaking an annular core made of ferspinel structure comprising lomeans of an incandescent wire arranged adjacent a predetermined line on said core.

If necessary the ring may be the ring the second time.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A METHOD OF BREAKING AN ANNULAR CORE MADE OF FERROMAGNETIC POLYOXIDE OF SPINEL STRUCTURE OF IRON COMPRISING PLACING A HEAT SOURCE ADJACENT SAID CORE AND LOCALLY HEATING SAID CORE TO THEREBY SPLIT THE SAME ALONG AT LEAST ONE PREDETERMINED LINE. 